Hydraulic expansive reamer



March 5, 1935.

J. J. SANTIAGO HYDRAULI C EXPANS I VE BEAMER Filed Sept. 5, 1933 Eig. 2

and may be considered primarily as a valve member, although it may alsoperform as a pressure head, as will be pointed out. Lower head 32operates in a liner 33 which forms the lower reduced part of thecylinder bore; this head carries packing 34 and fits the liner boreclosely. The liner rests at its lower end on body shoulder' 33a, and acompression spring 35 rests on the upper endof the liner and pushesupwardly on upper head 30 to move the plunger upwardly and normally tohold it in its upper position, (Fig. 1) .v

In this position of the plunger cutters 12 are collapsed; when theplunger moves down the cutters are expanded.

In the normal position of Fig. 1 lower plunger head 32 covers the port16a where passage 16 communicates with the cylinder bore. The long skirt30h of upper head 30 lies above the relief port 40 such a distance thatpreferably that port is not covered by head 30 until about the time port16a is opened by head 32. The drawing shows such relative positions ofthe ports that port 40 begins to close as port 16a begins to open; it ispreferable that the two ports be not fully open together.

When uid pressure from the drill pipe is applied to the plunger in theposition of Fig. 1, that pressure, acting on -the lower head 32 causesthe plunger to move down, and to expand the cutters, under the fullfluid pressure relieved only by the small port 40. The action ofexpansion is therefore positive, and under almost full pressure, untilcirculation port 16a is opened. Port 16a (passage 16) is of a size toallow relatively free circulation from the cylinder bore, but is smallerthan the passage through the drill pipe (indicated at 41), so thatsufficient back pressure is set up in the cylinder still to force theplunger down. And, additionally, there is some pressure exerteddownwardly on upper head 30, although the passages 30a have a largerarea thanpassage 16 and the back pressure above head 30 is thereforesmaller than that on lower head 32. The back pressure on head 30 may beincreased by making openings 30a smaller; they may be made in total areaas small as that of passage 16;` but I prefer to keep them relativelylarge to minimize wear 1ianddto keep higher the back pressure on thelower In any case, the pressure on the lower head after port 16a opens,is sufficient to cause complete cutter expansion. Port 16a does not openuntil the cutters are well toward the fully expanded position of Fig. 2;the dotted lines show cutter positions with the port about halfuncovered. At this time relief port 40 is closed or closing; and, thecutters being then far enough out to take a biting engagement with vthewall of the hole, the fluid pressure on the plunger and the upwardthrust of the formation on the cutters as the tool is lowered, cause thecompletion of positive expansion. Port 16a may be lowered if desired toa point where'the cutters are substantially completely expanded when theport is uncovered, but I prefer to have it uncovered and fluidcirculation to the cutters begin, at about the time the cutters reachthe position shown and begin cutting more or less fully.

On relief of pressure the spring immediately moves the plunger up andcollapses the cutters.

Relief port 40 is then open` and allows drainage of fluid from the drillpipe as it is raised from the hole. A relatively small port at 40suffices for drainage-a port much smaller than pipe passage 41 orcirculation passage 16; so that port 40,

to care for drainage, does not have to be largefV enough to relieve anyconsiderable fraction of' the pressure in the cylinder. And the size ofport 40 may be changed to suit differing situations; it may be enlargedif work is being done in soft strata where expansion is easy; it may bereduced where expansion is difficult. Provision of port 40 in theremovable bushing 40a facilitates such change by substitution; and thebushings may be of hardened steel to minimize wear of the orifice. Andwhenever that port becomes Worn by the fluid flow, the bushing may bereplaced by a `new one. In cases where expansion is exceptionallydifficult a solid plug may be substituted for the bushing so that fullunrelieved pressure is then exerted on the plunger. And the suggestedlower placement of port 16a provides for a longer application of thatfull pressure. I prefer, however, to use a bushing with at least a smallport 40 wherever possible, to provide for drainage.

I claim:

1. In an hydraulic expansive tool, a body with a cylinder therein, anexpansively movable cutter on the body, a plunger movable in thecylinder, connected to the cutter to move it and exposed to fluidpressure from the drill pipe to which the body is connected, acirculation port leading from the cylinder and discharging from thebody, and a relief port leading from the cylinder, said circulation portarranged to be opened by movement of the plunger in cutter expandingdirection, and said relief port being closed by the same movement of theplunger.

2. In an hydraulic expansive tool, a body with a cylinder therein, anexpansively movable cutter on the body, a plunger movable in thecylinder, connected to the cutter to move it and exposed to fluidpressure from the drill pipe to which the body is connected, acirculation port leading from the cylinder and discharging from thebody, and a relief port leading from the cylinder, said circulation portarranged to be opened by movement of the plunger in cutter expandingdirection, and

said relief port being closed by the same movement .i

iid

on the body, a plunger movable in the cylinder,

connected to the cutter to move it and exposed to uid pressure from thedrill pipe to which the body is connected, a circulation port leadingfrom the cylinder and discharging from the body, and a relief portleading from the cylinder, said circulation port arranged to be openedby movement of the plunger in cutter expanding direction, and saidrelief port being closed by the same movement of the plunger, and saidrelief port being formed in a removable and substitutable bushingwhereby the size of the relief port may be adjusted.

4. In an hydraulic expansive tool, a body with a cylinder therein, anexpansively movable cutter on the body, a plunger movable in thecylinder, connected to the cutter to move it and exposed to fluidpressure from the drill pipe to which the body is connected, acirculation port leading from the cylinder and discharging from thebody, and a relief port leading from the cylinder, said circulation portarranged to be opened by movement of the plunger in cutter expandingdirection, said relief port being closed by the same movement ofculation port, and said relief port being formed in a removable andsubstitutable bushing whereby the size of the relief port may beadjusted.

5. In an hydraulic expansive tool, a body with` -a cylinder thereinwhose upper end'is in communication with the drill pipe to which thebody is attached, an expansively movable cutter on the body, a plungermovable in the cylinder and connected to the cutter to move it, theplunger having a lower head tting the cylinder and an upper passagedhead also fitting the cylinder, a circulation passage leading from thecylinder at a point to be uncovered by the lower head on downwardmovement of the plunger, and a relief port leading from the cylinder ata point to be covered by the upper head on downward movement of theplunger.

6. In an hydraulic expansive tool, a body with a cylinder therein whoseupper end is in communication with the drill pipe to which the body isattached, an expansively movable cutter on the body, a plunger movablein the cylinder and connected to the cutter to move it, the plungerhaving a lower head tting the cylinder and an upper passaged head alsotting the cylinder, a circulation passage leading from the cylinder at apoint to be uncovered by the lower head on downward movement of theplunger, and a relief Yport leading from the cylinder at a point to becovered by the upper head on downward movement of the plunger at a timenot later than the uncovering of the circulation passage.

7. In an hydraulic expansive tool, a body with a cylinder therein whoseupper end is in communication with the drill pipe to which the body isattached, an expansively movable cutter on the body, a plunger movablein the cylinder and connected to the cutter to move it, the plungerhaving a lowerhead tting the cylinder and an upper passaged head alsofitting the cylinder, a circulation passage leadingfrom the cylinder ata point to be uncovered by the lower head on downward movement of theplunger, and a relief port leading from the cylinder at a point to becovered by the upper head on downward movement of the plunger, saidrelief port being formed in a bushing whereby its effective size may beadjusted.

JAMES J. SANTIAGO.

